I like snails, they're good at cleaning up and stray detritus, when they become a problem it is usually a sign that there is too much detritus, decaying food etc at the bottom of the tank, you can either improve the circulation of the tank, use a gravel vacuum cleaner to remove any muck, or you can cut back on food, fish do not need feeding daily as the manufacturers have us believe, I tend to feed my fish every 2-3 days, I don't have any problems with snails, detritus or algae etc.
For removing snails you can place a piece of cucumber in the tank at night and then remove it in the morning, hopefully it wil, have attracted the snails and you can remove a fair few at a time, there are assassin snails too which have already been mentioned, although they only average 2 snails per week, if you have enough of them they can clean up an infestation pretty quickly, but I prefer to crush them and feed them to my fish.